[The effects of nerve growth factor-induced apoptosis on hepatic stellate cells of fibrotic rat liver].

Objective: To evaluate the effects of nerve growth factor (NGF) on the proliferation and apoptosis of hepatic stellate cells (HSCs) of fibrotic rat.
Methods: HSCs of fibrotic rat were incubated in medium with different concentrations of NGF (50 ng/ml, 100 ng/ml, and 150 ng/ml respectively) or without NGF for 24, 48 and 72 hours respectively. The proliferation rate of the HSCs was determined by MTT assay. Apoptotic HSCs were detected by TUNEL method. The apoptotic rate of HSCs was studied by flow cytometry. The conformation of HSCs was observed by microscopy.
Results: (1) MTT method indicated that the proliferation rates of the HSCs induced with different concentrations of NGF for 24 hours was significantly reduced compared with that of the control group (0.77 +/- 0.03, all P < 0.05). The proliferation rate of the HSCs treated with NGF of the concentration of 100 ng/ml for 24 hours was the lowest (0.63 +/- 0.02, P < 0.05). (2) The proliferation rate of the HSCs treated with NGF of the concentration of 100 ng/ml, the most appropriate concentration, increased time-dependently, and the proliferation rate at the 72 th hour was the lowest in comparison with that of the control group (0.48 +/- 0.03 vs 0.89 +/- 0.01, P < 0.05). (3) After stimulation of the HSCs by NGF of the concentration of 100 ng/ml for 24 hr, TUNEL method showed a significant increased apoptotic rate of HSCs compared with the control group (10.2% +/- 1.2% vs 1.6% +/- 0.1%, P < 0.05). Meanwhile, flow cytometry showed an apoptotic rate of 6.2% +/- 0.2% among the HSCs in the experimental group, but no apoptosis in control group. (4) Microscopy did not show significant morphological change in the HSCs with the proliferation inhibited.
Conclusion: NGF can induce apoptosis of activated HSCs. The mechanism may be the interference with the apoptotic pathway.